Direct acting extensible and retractable arm mechanism, and robot arm provided with direct acting extensible and retractable arm mechanism

ABSTRACT

A robot arm ( 50 ) of the present invention includes, as a direct acting extensible/retractable joint (J 3 ), an arm section ( 2 ) constituted by an upper structure group ( 20 ) and a lower structure group ( 21 ). Groups ( 20 ) and ( 21 ), having an arrangement in which structures are connected in series, partially engage so as to form a direct rigid combined structure, and are separated so as to release the rigid structure. An arm length can be adjusted arbitrarily. Section ( 2 ) can have a plane surface having no gap to prevent entry of a finger/dust. Separation of Groups ( 20 ) and ( 21 ) allows an upper structure ( 22 ) and a lower structure ( 23 ) to rotate around their rotational axes, to realize compact storage inside a robot arm supporting member ( 1 ). It is thus possible to prevent significantly entry of a finger/dust, and provide a compact direct acting extensible and retractable arm mechanism.

TECHNICAL FIELD

The present invention relates to a mechanism of a robot arm.Specifically, the present invention relates to (i) a direct actingextensible and retractable arm mechanism which realizes high safety, acompact body, and prevention of entry of dust and the like, and (ii) arobot arm including the direct acting extensible and retractable armmechanism.

BACKGROUND ART

In recent years, there has been a reduction in population of workers inan aging society with a falling birthrate. Because of such a reductionin population of workers, there has been demand for a robot arm which(i) can manufacture a product in cooperation with a human at aproduction site or (ii) can support a daily life of an old person or adaily life of a handicapped person.

A robot arm constituted by rotational joints has an arrangement in whicha plurality of rotational joints 103 and a plurality of arm sections 102are, alternately, connected to each other in series between a base 100and an end effector 101 (see (a) and (b) of FIG. 19). With thearrangement, in a case where a position and orientation of the endeffector 101 are determined, rotational angles of the plurality ofrotational joints 103 are generally determined uniquely. That is, thereis a problem that it is not possible to determine arbitrarily theposition of the end effector 101 and a position of each of therotational joints 103. For this reason, in a case where the end effector101 is moved from a position illustrated in (a) of FIG. 19 to a positionillustrated in (b) of FIG. 19, for example, the plurality of armsections 102 become close to each other. In this case, there is anincrease in risk that an object located in the vicinity of the pluralityof arm sections 102 might be sandwiched between the plurality of armsections 102. Further, since one of the plurality of rotational joints103 is moved upward in FIG. 19 from a straight line (shown in a dashedline) connecting the base 100 and the end effector 101 to each other,there is an increase in risk that the one of the plurality of rotationaljoints 103 becomes in contact with, or crashes against an object locatedin the vicinity of the robot arm. Such an arrangement is not suitablyapplicable to a robot arm which operates in the vicinity of a person ina daily life or the like.

In order to reduce such risks, there has been proposed a robot armhaving a direct acting extensible and retractable arm mechanism whichemploys a direct acting joint in place of a rotational joint. The directacting extensible and retractable arm mechanism employs linearextensible and retractable motion, and has been applied to a cranevehicle, a ladder truck, etc. In order to ensure a high rigidity, thelinear extensible and retractable arm mechanism, applied to the cranevehicle, the ladder truck, etc., is such that a mechanism of an armsection becomes larger with increasing distance from a hand sectiontoward a root section serving as a base section. Accordingly, it isnecessary for the direct acting extensible and retractable armmechanism, applied to the crane vehicle, the ladder truck, etc., to havethe base section and the arm section, both of which are large and heavy.

Further, Patent Literatures 1 through 3 also describe a robot arm havinga linear extensible and retractable arm mechanism. However, such a robotarm has danger in a case where the robot arm operates in the vicinity ofa human in a daily life or the like. Further, a general direct actingmechanism used in an industrial machine keeps its linear mechanism allthe time. For this reason, in a case where the direct acting mechanismis stored, the direct acting mechanism thus stored protrudes from a mainbody of the robot arm. That is, there remains danger for a human in acase where the direct acting mechanism operates in the vicinity of thehuman in a daily life or the like.

Patent Literature 4 describes an arm employing a direct extensible andretractable arm mechanism, which arm has a low risk that the arm mightbe in contact with or crush against an object located in the vicinity ofthe arm. However, this arm ensures its rigidity only in a direction ofgravitational forth. That is, the arm is not suitably used as a robotarm that is used in a daily life or the like, in which (i) realizationof an arbitrary position of the arm and an arbitrary posture of the armare required, and (ii) various operations are required, such as holdingan object with an end effector, pressing a button, and exhibiting forcenot only in the direction of gravitational force but also in directionsof 6 axes of a position and a posture. Furthermore, since an overloadconcentrates on an axis, it is difficult to ensure a high rigidity ofthe arm. Moreover, since a lot of gaps are formed on an upper surfacebetween links, it is likely that (i) a finger is sandwiched inside thedirect acting extensible and retractable arm mechanism and (ii) dustenters inside the direct acting extensible and retractable armmechanism. That is, this arm cannot be suitably used as a robot ram usedin the vicinity of a human in various environments, e.g., when beingused in a daily life.

CITATION LIST

[Patent Literature 1]

Japanese Patent Application Publication, Tokukaihei, No. 7-164369 A(1995) (Publication Date: Jun. 27, 1995)

[Patent Literature 2]

Japanese Patent Application Publication, Tokukaisho, No. 61-45168 A(1986) (Publication Date: Mar. 5, 1986)

[Patent Literature 3]

Japanese Patent Application Publication, Tokukaisho, No. 63-84882 A(1988) (Publication Date: Apr. 15, 1988)

[Patent Literature 4]

Japanese Patent Application Publication, Tokukaihei, No. 6-39758 A(1994) (Publication Date: Feb. 15, 1994)

SUMMARY OF INVENTION Technical Problem

As to a robot arm which (i) operates in the vicinity of a human to (i)produce a product in cooperation with the human at a production site or(ii) operates in the vicinity of an aged person or a handicapped personto support a daily life of the aged person or a daily life of thehandicapped person, use of a direct acting extensible and retractablearm mechanism in place of a rotational joint leads to an improvement insafety. However, with such a direct acting extensible and retractablearm mechanism, there are such problems that (i) it is difficult toensure a high rigidity for each of positions and postures of the directacting extensible and retractable arm mechanism, (ii) it is difficult toprevent a finger from being sandwiched inside the direct actingextensible and retractable arm mechanism or dust from entering thedirect acting extensible and retractable arm mechanism, and (iii) thedirect acting extensible and retractable arm mechanism has a large sizewhen being stored.

The present invention is made in view of the problems. An object of thepresent invention is to provide a direct acting extensible andretractable arm mechanism of a robot arm which can be used safely in thevicinity of a human in a daily life or the like.

Solution to Problem

The inventors of the present invention has completed the presentinvention by finding such a direct acting extensible and retractable armmechanism that (i) two structure groups constitute a single arm section,(ii) the arm section has a flexible extensibility and a flexibleretractility, (iii) the arm section has a high rigidity and a highstrength in such a manner that the arm section becomes rigid in a casewhere the two structure groups overlap each other to form the armsection in cooperation with each other, (iv) particularly, the armsection can cause a surface, via which entry of a finger or dust islikely to occur, to be a plane surface having no gap, and (v) the directacting extensible and retractable arm mechanism can be reduced in sizewhen being stored in such a manner that each of a plurality ofstructures constituting the one of the two structure groups and each ofa plurality of structures constituting the other one of the twostructure group can be rotate around a rotational axis in a case wherethe two structure groups are separated from each other.

That is, in order to attain the object, a direct acting extensible andretractable arm mechanism of the present invention includes: a robot armsupporting member; a robot arm supporting member; and an arm sectionbeing extensible and retractable directly from one of ends of the robotarm supporting member, the arm section being such that a hand section isattachable to one of ends of the arm section, the arm section beingconstituted by (i) a first structure group in which a plurality of firststructures are coupled with each other in series in such a manner thatadjacent ones of the plurality of first structures are coupled with eachother via a corresponding one of a plurality of first coupling axes in adirection which is orthogonal to a direction of the corresponding one ofthe plurality of first coupling axes and (ii) a second structure groupin which a plurality of second structures are coupled with each other inseries in such a manner that adjacent ones of the plurality of secondstructures are coupled with each other via a corresponding one of aplurality of second coupling axes in a direction which is orthogonal toa direction of the corresponding one of the plurality of second couplingaxes, the plurality of first structures being identical with each otherin width in a direction parallel to the plurality of first couplingaxes, the plurality of second structures being identical with each otherin width in a direction parallel to the plurality of second couplingaxes, the first structure group and the second structure group beingcoupled with each other in such a manner that one of two end firststructures of the plurality of first structures, on a hand section side,and one of two end second structures of the plurality of secondstructures, on the hand section side, are coupled with each other, therobot arm supporting member including drive means for (i) pressing thefirst structure group and the second structure group so that the firststructure group and the second structure group become closer to eachother and become in contact with each other, (ii) causing the firststructure group and the second structure group to overlap each other sothat a surface of the first structure group and a surface of the secondstructure group, which surfaces are in contact with each other, do notslip with respect to each other, and (iii) driving the first structuregroup and the second structure group in a direction in which the armsection is extensible, in a case where the drive means causes the firststructure group and the second structure group to overlap each other,the first structure group and the second structure group forming such arigid arm section that rotation of each of the plurality of firststructures via the corresponding one of the plurality of first couplingaxes and rotation of each of the plurality of second structures via thecorresponding one of the plurality of second coupling axes areprevented, at least one of the first structure group and the secondstructure group is such that adjacent ones of structures engage witheach other via their side surfaces, and form a plane surface having nogap, which plane surface faces and is in contact with a surface of theother one of the first structure group and the second structure group,the robot arm supporting member including separation means in the robotarm supporting member, in a case where the drive means carries outreverse driving, the separation means causes the first structure groupand the second structure group to be separated from each other so that(i) each of the plurality of first structures is rotatable around thecorresponding one of the plurality of first coupling axes and (ii) eachof the plurality of second structures is rotatable around thecorresponding one of the plurality of second coupling axes.

Additional objects, features, and strengths of the present inventionwill be made clear by the description below. Further, the advantages ofthe present invention will be evident from the following explanation inreference to the drawings.

Advantageous Effects of Invention

As described above, a direct acting extensible and retractable armmechanism of the present invention includes: a robot arm supportingmember; a robot arm supporting member; and an arm section beingextensible and retractable directly from one of ends of the robot armsupporting member, the arm section being such that a hand section isattachable to one of ends of the arm section, the arm section beingconstituted by (i) a first structure group in which a plurality of firststructures are coupled with each other in series in such a manner thatadjacent ones of the plurality of first structures are coupled with eachother via a corresponding one of a plurality of first coupling axes in adirection which is orthogonal to a direction of the corresponding one ofthe plurality of first coupling axes and (ii) a second structure groupin which a plurality of second structures are coupled with each other inseries in such a manner that adjacent ones of the plurality of secondstructures are coupled with each other via a corresponding one of aplurality of second coupling axes in a direction which is orthogonal toa direction of the corresponding one of the plurality of second couplingaxes, the plurality of first structures being identical with each otherin width in a direction parallel to the plurality of first couplingaxes, the plurality of second structures being identical with each otherin width in a direction parallel to the plurality of second couplingaxes, the first structure group and the second structure group beingcoupled with each other in such a manner that one of two end firststructures of the plurality of first structures, on a hand section side,and one of two end second structures of the plurality of secondstructures, on the hand section side, are coupled with each other, therobot arm supporting member including drive means for (i) pressing thefirst structure group and the second structure group so that the firststructure group and the second structure group become closer to eachother and become in contact with each other, (ii) causing the firststructure group and the second structure group to overlap each other sothat a surface of the first structure group and a surface of the secondstructure group, which surfaces are in contact with each other, do notslip with respect to each other, and (iii) driving the first structuregroup and the second structure group in a direction in which the armsection is extensible, in a case where the drive means causes the firststructure group and the second structure group to overlap each other,the first structure group and the second structure group forming such arigid arm section that rotation of each of the plurality of firststructures via the corresponding one of the plurality of first couplingaxes and rotation of each of the plurality of second structures via thecorresponding one of the plurality of second coupling axes areprevented, at least one of the first structure group and the secondstructure group is such that adjacent ones of structures engage witheach other via their side surfaces, and form a plane surface having nogap, which plane surface faces and is in contact with a surface of theother one of the first structure group and the second structure group,the robot arm supporting member including separation means in the robotarm supporting member, in a case where the drive means carries outreverse driving, the separation means causes the first structure groupand the second structure group to be separated from each other so that(i) each of the plurality of first structures is rotatable around thecorresponding one of the plurality of first coupling axes and (ii) eachof the plurality of second structures is rotatable around thecorresponding one of the plurality of second coupling axes.

According to the arrangement, it is possible to provide a direct actingextensible and retractable arm mechanism of a robot arm that (i) cansolve conventional problems that (1) it is difficult to ensure a highrigidity for each of positions and postures of the direct actingextensible and retractable arm mechanism, (2) it is difficult to preventa finger from being sandwiched inside the direct acting extensible andretractable arm mechanism or dust from entering the direct actingextensible and retractable arm mechanism, and (3) the direct actingextensible and retractable arm mechanism has a large size when beingstored, and (ii) can be used in the vicinity of a human in a daily lifeor the like.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating an outer appearance of a robotarm in accordance with an embodiment of the present invention.

FIG. 2 is a cross-sectional view partially illustrating a direct actingextensible and retractable mechanism in accordance with the embodimentof the present invention.

FIG. 3 is a perspective view illustrating an outer appearance of anarrangement of a part of the direct acting extensible and retractablearm mechanism in accordance with the embodiment of the presentinvention.

FIG. 4 is a perspective view illustrating an outer appearance of anarrangement of a part of the direct acting extensible and retractablearm mechanism in accordance with the embodiment of the presentinvention.

FIG. 5 is a perspective view illustrating an outer appearance of anarrangement of a part of the direct acting extensible and retractablearm mechanism in accordance with the embodiment of the presentinvention.

FIG. 6 is a perspective view illustrating an outer appearance of anarrangement of a part of the direct acting extensible and retractablearm mechanism in accordance with the embodiment of the presentinvention.

FIG. 7 is a cross-sectional view partially illustrating the directacting extensible and retractable arm mechanism in accordance with theembodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 11 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 12 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 13 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 14 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 15 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 16 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 17 is a view illustrating a modified example of the direct actingextensible and retractable arm mechanism in accordance with theembodiment of the present invention: (a) of FIG. 17 is a top view; and(b) of FIG. 17 is a front view.

FIG. 18 is a cross-sectional view illustrating a modified example of thedirect acting extensible and retractable arm mechanism in accordancewith the embodiment of the present invention.

FIG. 19 is a view illustrating a conventional arrangement.

DESCRIPTION OF EMBODIMENTS

A direct acting extensible and retractable arm mechanism of the presentinvention can (i) ensure a high rigidity for all positions and allpostures of an arm section which is extensible and retractable directlyfrom one of ends of a robot arm supporting member, (ii) prevent a fingeror the like from being sandwiched or prevent dust from entering the armsection, and (iii) have a reduction in size when being stored. For thesereasons, the direct acting extensible and retractable arm mechanism canbe applied not only to a robot arm for supporting safely a daily life ofa handicapped person or a daily life of an aged person, in the vicinityof that person, but also to, for example, a next-generation robot armfor cellular manufacturing, which operates in cooperation with a human.

One embodiment of the present invention is described below withreference to FIGS. 1 through 10. Note that the entire direct actingextensible and retractable arm mechanism may be regarded as a singleoperational joint, and may be referred to as “direct acting extensibleand retractable arm joint J3”, in some cases.

FIG. 1 is a perspective view illustrating an outer appearance of a robotarm, which is one embodiment of the direct acting extensible andretractable arm mechanism of the present invention.

A robot arm 50 includes: a robot arm supporting member 1 (base); an armsection 2; and a hand section 3 (end effector) (see FIG. 1).

[Robot Arm Supporting Member]

The robot arm supporting member 1 has a structure that extends, from aninstallation surface G on which the robot arm 50 is installed, in adirection vertical to the installation surface G. The robot armsupporting member 1 supports the entire robot arm 50 (see FIG. 1).

The robot arm supporting member 1 includes a first supporting section 10a, a second supporting section 10 b, a third supporting section 10 c, afirst rotational joint J1 (rotational joint means), and a secondrotational joint J2 (see FIG. 1).

The first supporting section 10 a and the second supporting section 10 bhave a hollowed shape (see FIG. 1). The first supporting section 10 aand the second supporting section 10 b are arranged in a lower positionand an upper position, respectively, so that a center axis (supportingaxis) of the first supporting section 10 a and a center axis (supportingaxis) of the second supporting section 10 b match each other. The thirdsupporting section 10 c also has a hollowed structure, which is incommunication with both the hollowed structure of the first supportingsection 10 a and the hollowed structure of the second supporting section10 b. A part of constituent elements of the arm section 2 (laterdescribed) is arranged so as to be storable inside these sections, thatis, the first supporting section 10 a, the second supporting section 10b, and the third supporting section 10 c.

The first rotational joint J1 is provided between the first supportingsection 10 a and the second supporting section 10 b, and is constitutedas a rotational joint whose rotational axis is a center axis (the centeraxis of the first supporting section 10 a and the center axis of thesecond supporting section 10 b) of the robot arm supporting member 1.Rotation of the first rotational joint J1 causes the second supportingsection 10 b, the third supporting section 10 c, the arm section 2, andthe hand section 3 to be rotated around the rotational axis of the firstrotational joint J1.

The second rotational joint J2 is provided at one of ends of the secondsupporting section 10 b on an arm section 2 side (see FIG. 1), and isconstituted as a rotational joint whose rotational axis is orthogonal tothe axis of the robot arm supporting member 1. Rotation of the secondrotational joint J2 causes the third supporting section 10 c, the armsection 2, and the hand section 3 to be rotated around the rotationalaxis of the second rotational joint J2 with respect to the robot armsupporting member 1. Further, the second rotational joint J2 has acertain angle and a certain distance from the center axis of the robotarm supporting member 1 so that an object located around the robot arm50 would not be tightly sandwiched between the robot arm supportingmember 1 and the arm section 2.

According to the present embodiment, the robot arm supporting member 1extends from the installation surface G in the direction vertical to theinstallation surface G. Note, however, that the present invention is notlimited to this, as long as the robot arm supporting member 1 extendsfrom the installation surface G while having a certain angle withrespect to the installation surface G.

[Hand Section]

The hand section 3 is provided at one of ends of the arm section 2. Thehand section 3 includes a fourth rotational joint J4, a fifth rotationaljoint J5, a sixth rotational joint J6, a seventh rotational joint J7, afirst finger 70, and a second finger 71 (see FIG. 1). Note that thefirst finger 70 and the second finger 71 constitute a two-finger hand72.

The fourth rotational joint J4 is a rotational joint whose rotation axisis a center axis (hereinafter, referred to as “arm axis”, in some cases)of the arm section 2, which center axis extends in a direction in whichthe arm section 2 is extensible and retractable. Rotation of the fourthrotational joint J4 causes the hand section 3 (a part from one of endsof the hand section 3, i.e., the fourth rotational joint J4, to theother one of ends of the hand section 3) to be rotated around therotational axis of the fourth rotational joint J4.

The fifth rotational joint J5 is a rotational joint whose rotationalaxis is orthogonal to the arm axis. Rotation of the fifth rotationaljoint J5 causes the two-finger hand 72 (a part from one of ends of thefifth rotational joint J5 to the other one of ends of the hand section3) to be rotated around the rotational axis of the fifth rotationaljoint J5.

The sixth rotational joint J6 is a rotational joint whose rotationalaxis is orthogonal to both the arm axis and the fifth rotational jointJ5. Rotation of the sixth rotational joint J6 causes the two-finger hand72 to be rotated around the rotational axis of the sixth rotationaljoint J6. Here, the first finger 70 and the second finger 71 keep adistance between these, and are rotated, in synchronization with eachother, around the rotational axis of the sixth rotational joint J6.

The seventh rotational joint J7 causes the first finger 70 and thesecond finger 71 of the two-finger hand 72 to be rotated. That is, theseventh rotational joint J7 can cause one of ends of the first finger 70and one of ends of the second finger 71 to be rotated, and therefore tobe close to each other. In this case, the two-finger hand 72 is closedso as to hold an object. On the other hand, the seventh rotational jointJ7 can cause the one of ends of the first finger 70 and the one of endsof the second finger 71 to be rotated, and therefore to be away fromeach other. In this case, the two-finger hand 72 is opened so as torelease the object held by the two-finger hand 72.

According to the present embodiment, the two-finger hand 72 is used asthe hand section 3. Note, however, that the present invention is notlimited to this, and the hand section 3 may be a hand having not lessthan three fingers. Further, the hand section 3 is not limited to a handhaving a finger section(s), and any desired sorts of structure, requiredto be at a desired position or to have a desired posture by use of thearm section, can be connected to the arm section in place of the handsection 3. For example, it is possible to connect a device having animage capturing function to the arm section, in place of the handsection 3.

Note that the scope of the direct acting extensible and retractable armmechanism of the present invention also encompasses an arrangement inwhich the hand section 3 is not connected.

[Arm Section]

The arm section 2 includes a direct acting extensible and retractablearm joint J3 illustrated in FIG. 1. The hand section 3 is provided atone of ends of the arm section 2. The hand section 3 is provided withthe two-finger hand 72. The robot arm supporting member 1, the armsection 2, and the hand section 3 can cause, in cooperation with eachother, the two-finger hand 72 to be moved to a desired position or movedto have a desired posture. In a state illustrated in FIG. 1, the directacting extensible and retractable arm joint J3 can be extended so as tocause the two-finger hand 72 to be moved to a position away from therobot arm supporting member 1. Alternatively, the direct actingextensible and retractable arm joint J3 can be retracted so as to causethe two-finger hand 72, which is located away from the robot armsupporting member 1, to be moved to be closer to the robot armsupporting member 1.

FIG. 2 is a fragmentary cross-sectional view partially illustrating therobot arm 50, taken along a cutting line of A-A′ shown in FIG. 1.

As illustrated in FIG. 2, the arm section 2 is mainly constituted by (i)an upper structure group 20 and a lower structure group 21, whichconstitute the direct acting extensible and retractable arm joint J3,and (ii) drive means 40 (drive mechanism) for driving the direct actingextensible and retractable arm joint J3.

The direct acting extensible and retractable arm joint J3 can constitutethe arm section 2 that (i) is stored in the robot arm supporting member1 extending, from the installation surface 50 on which the robot arm 50is installed, in the direction vertical to the installation surface 50,and (ii) is extensible from the robot arm supporting member 1 via thethird supporting section 10 c (see FIG. 1). Here, the direct actingextensible and retractable arm joint J3 is arranged such that the lowerstructure group 20 is provided at a lower position with respect to theupper structure group 20 in a direction of gravitational force.Overlapping of the upper structure group 20 and the lower structuregroup 21 causes both the upper structure group 20 and the lowerstructure group 21 to become rigid, so that the upper structure group 20and the lower structure group 21 form the arm section 2. The secondrotational joint J2 causes the arm section 2 to be rotated around thesecond rotational joint J2.

(Common Block Member)

A common block member 60 is attached to both (i) one of ends of theupper structure group 20 and (ii) one of ends of the lower structuregroup 21 (see FIGS. 2, 3, 5, and 7). An upper structure 22, providedadjacent to the common block member 60, is coupled with the common blockmember 60. A lower structure 23, provided adjacent to the common blockmember 60, is also coupled with the common block member 60. The commonblock member 60 has such a shape that a single upper structure 22 and asingle lower structure 23 are formed integral with each other.

According to the present embodiment, the common block member 60 has suchan integral shape. Note, however, that the present invention is notlimited to this, as long as the one of ends of the upper structure group20 and the one of ends of the lower structure group 21 are not away fromeach other inconveniently in an extending/retracting operation of thedirect acting extensible and retractable arm joint J3. Accordingly, itis possible to employ, as the common block member 60, not only theaforementioned member but also such a member that a single upperstructure 22 and a single lower structure 23 are attached to each otherby use of an adhesive or by welding. Furthermore, it is also possible toemploy, as the common block member 60, such a member that a single upperstructure 22 and a single lower structure 23 are formed integral witheach other by use of a fixing mechanism. Moreover, it is also possibleto employ, as the common block member 60, such a member that a singleupper structure 22 and a single lower structure 23 are not attached toeach other but are pressed with respect to each other to be in contactwith each other, and are covered with a cover case.

According to the present embodiment, the common block member 60 has sucha shape that the upper structure 22 and the lower structure 23 areformed integral with each other. Note, however, that the presentinvention is not limited to this. In a case where it is unnecessary tostore the common block member 60 in the robot arm supporting member 1via the third supporting section 10 c, it is possible that both the oneof ends of the upper structure group 20 and the one of ends of the lowerstructure group 21 are formed integral with each other, and areconnected to a common block member 60 having an arbitrary shape.

Lower Structure Group

The lower structure group 21 is constituted by a plurality of lowerstructures 23 (see FIG. 2). All the plurality of structures 23 areconnected to each other in series (from one of two end lower structures23 to the other one of two end lower structures 23).

Further, adjacent ones of the plurality of lower structures 23 arecoupled with each other via a rotational axis (coupling axis) (laterdescribed) in a direction orthogonal to the rotational axis.Furthermore, the plurality of lower structures 23 are identical witheach other in size (width) in a direction parallel to the coupling axis.

The following description deals with details of each of coupling partsof the lower structure group 21 and details of an arrangement of each ofthe plurality of lower structures 23, with reference to FIGS. 3 and 4.FIG. 3 is a perspective view illustrating an outer appearance of a partof the lower structure group 21. Further, FIG. 4 is a perspective viewillustrating an outer appearance of a single lower structure 23.

First, the following description deals with a coupling part of the lowerstructure group 21. Adjacent ones of the plurality of lower structures23 are coupled with each other via a rotational axis, e.g., a bearingemploying a pin 30. Specifically, a lower structure 23 has a throughhole 25 at a coupling part between the lower structure 23 and one ofadjacent lower structures 23, and a through hole 26 at another couplingpart between the lower structure 23 and the other one of the adjacentlower structures 23. Both the thorough hole 25 a and the through hole 25b extend in a direction vertical to a coupling direction. Adjacent onesof the plurality of lower structures 23, each having the abovestructure, are coupled with each other such that a through hole 25 a ofone of the adjacent ones of the plurality of lower structures 23 and athrough hole 25 b of the other one of the adjacent ones of the pluralityof lower structures 23 are coupled with each other. That is, the throughhole 25 a of the one of the adjacent ones of the plurality of lowerstructures 23 and the through hole 25 b of the other one of the adjacentones of the plurality of lower structures 23 form, in cooperation witheach other, a single through hole. A single pin 30 is inserted into thesingle through hole so that the adjacent ones of the plurality of lowerstructures 23 are coupled with each other. According to the presentembodiment, the coupling part between adjacent ones of the plurality oflower structures 23 is such that (i) one of ends of one of the adjacentones of the plurality of lower structures 23 has a convex structurehaving a through hole 25 b, (ii) one of ends of the other one of theadjacent ones of the plurality of lower structures 23 has a concavestructure having a through hole 25 a, and (iii) the convex structureengages with the concave structure so as to form a single through hole(see FIG. 4). Note, however, that the present invention is not limitedto this coupling method.

Next, the following description deals with a structure of each of theplurality of lower structures 23. As illustrated in FIGS. 3 and 4, eachof the plurality of lower structures 23 is such that, in a case wherethe lower structure 23 is cut along a plane vertical to a longitudinaldirection, a cross-section of the lower structure 23 has a concave shape(where “longitudinal direction” is a direction in which adjacent ones ofthe plurality of lower structures 23 are coupled with each other, asdescribed later). In the present specification, an opened part of theconcave shape is referred to as “opening section”. Further, a surfacehaving the opening section is referred to as “upper surface” of thelower structure 23, in some cases. The upper surface indicates a surfacewhich is located at an upper position in the direction of gravitationalforce, in a case where the adjacent ones of the plurality of lowerstructures 23 are coupled with each other in a horizontal direction.

Under a condition that the adjacent ones of the plurality of lowerstructures 23 are coupled with each other and arranged linearly, openingsections of the adjacent ones of the plurality of lower structures 23are also coupled with each other, and therefore form such a singlegroove that structures having the concave shape are connected to eachother. An inner space of the groove can be used effectively as a spacein which an electrical line is provided along the groove.

Note that, in a case where it is unnecessary to obtain such an innerspace of the groove, it is possible that each of the plurality of lowerstructures 23 has not such a groove structure but a general blockstructure.

Further, surfaces of adjacent ones of the plurality of lower structures23, which surfaces face each other, can have, respectively, side surfaceconvex-concave structures 23 a (alignment sections) which engage witheach other (see FIG. 9). A side surface convex-concave structure 23 a ofone of adjacent ones of the plurality of lower structures 23 engageswith a side surface convex-concave structure 23 a of the other one ofthe adjacent ones of the plurality of lower structures 23, so that theadjacent ones of the plurality of lower structures 23 can be preventedsignificantly from being out of alignment in a coupling direction, at acoupling part between the adjacent ones of the plurality of lowerstructures 23, due to rotation around a rotational axis in the couplingdirection (see FIG. 9). This makes it possible to further increase arigidity of a combined structure of an upper structure and a lowerstructure.

Furthermore, since the surfaces of the adjacent ones of the plurality oflower structures 23, which surfaces face each other, have side surfaces23 b, respectively. Since the side surfaces 23 b are provided, it ispossible to prevent the adjacent ones of the plurality of lowerstructures 23 from being changed from (i) a state where the adjacentones of the plurality of lower structures 23 are arranged to beconnected to each other in series while concave opening sections of theadjacent ones of the plurality of lower structures 23 face in the samedirection to (ii) a state where the adjacent ones of the plurality oflower structures 23 are rotated to form a V shape while the concaveopening sections faces “inward” with respect to each other.

Meanwhile, it is possible to cause the adjacent ones of the plurality oflower structures 23 to be changed from (i) the state where the adjacentones of the plurality of lower structures 23 are arranged to beconnected to each other in series while concave opening sections of theadjacent ones of the plurality of lower structures 23 face in the samedirection to (ii) a state where the adjacent ones of the plurality oflower structures 23 are rotated to form a V shape while the concaveopening sections of the adjacent ones of the plurality of lowerstructures 23 face “outward” with respect to each other.

Moreover, it is possible that (i) adjacent ones of the plurality oflower structures 23 of the lower structure group 21 engage with eachother via their side surfaces, and therefore (ii) a surface of the lowerstructure group 21, which surface faces the upper structure group 20,becomes a plane surface having no gap. This arrangement can (i) preventan object from being sandwiched between adjacent ones of the pluralityof lower structures 23 and (ii) prevent dust from entering a spacebetween adjacent ones of the plurality of lower structures 23.

Further, an edge section is formed around each of opening sections ofthe plurality of lower structures 23, and is in contact with the upperstructure group 22 (later described). The edge section has an uppersurface convex-concave structure 23 c (engaging section) (see FIG. 9).The upper surface convex-concave structure 23 c is arranged so as toengage with a bottom surface convex-concave structure 22 a of each ofthe plurality of upper structures 22 (later described) (see FIG. 10).

Note that, in a case where a gear roller is attached, as a pressingroller 41, to a bottom surface of a part where the plurality of lowerstructures 23 of the lower structure group 21 are arranged to beconnected to each other in series in the horizontal direction, or in acase where an arrangement which is the same as a gear 34 is provided inplace of the pressing roller 41, a bottom surface convex-concavestructure 23 d which engages with such a gear is provided on the bottomsurface of each of the plurality of lower structures 23.

Upper Structure Group

The upper structure group 20 is constituted by plurality of upperstructures 22 (see FIG. 2). All the plurality of upper structures 22 areconnected to each other in series (from one of two end upper structures22 to the other one of two end upper structures 22).

Further, adjacent ones of the plurality of upper structures 22 arecoupled with each other via a rotational axis (coupling axis) (laterdescribed) in a direction orthogonal to the rotational axis.Furthermore, the plurality of upper structures 22 are identical witheach other in size (width) in a direction parallel to the coupling axis.

The following description deals with details of a coupling part ofadjacent ones of the plurality of upper structures 22, and anarrangement of each of the plurality of upper structures 22, withreference to FIGS. 5 and 6. FIG. 5 is a perspective view illustrating anouter appearance of a part of the plurality of upper structures 22.Moreover, FIG. 6 is a perspective view illustrating an outer appearanceof a single upper structure 22.

First, the following description deals with each of coupling parts ofthe upper structure group 20. Adjacent ones of the plurality of upperstructures 22 are coupled with each other via a rotational axis, such asa bearing employing a pin 31 (see FIG. 5). Specifically, each of theplurality of upper structures 22 has such a structure that (i) a part ofthe upper structure 22, which part is adjacent to one of adjacentstructures 22, has a through hole 24 a, (ii) another part of the upperstructure 22, which another part is adjacent to the other one ofadjacent upper structure 22, has a through hole 24 b, and (iii) both thethrough hole 24 a and the through hole 24 b extend in a directionvertical to the coupling direction. A through hole 24 a of one ofadjacent ones of the plurality of upper structures 22 and a through hole24 b of the other one of adjacent ones of the plurality of upperstructures 22 engage with each other, so as to form a single throughhole. A single pin 31 is inserted into the single through hole, so thatthe adjacent ones of the plurality of upper structures 22 are coupledwith each other. According to the present embodiment, the coupling partbetween adjacent ones of the plurality of upper structures 22 is suchthat (i) a part of one of the adjacent ones of the plurality of upperstructures 22, which part is adjacent to the other one of the adjacentones of the plurality of upper structures 22, has a convex structurehaving a through hole 24 a, and (ii) a part of the other one of theadjacent ones of the plurality of upper structures 22, which part isadjacent to the one of the adjacent ones of the plurality of upperstructures 22, has a concave structure having a through hole 24 b (seeFIG. 6). The convex structure engages with the concave structure so asto form a single through hole. Note, however, that the present inventionis not limited to this coupling method.

Adjacent ones of the plurality of upper structures 22, coupled with eachother, are rotatable with respect to each other around the pin 31 (seeFIG. 5) serving as a rotational axis.

Each of the plurality of upper structures 22 has a side surface 22 bwhich faces an adjacent upper structure 22 (see FIG. 6). The provisionof the side surface 22 b makes it possible that the adjacent ones of theplurality of upper structures 22 are changed from (i) a state where theadjacent ones of the plurality of upper structures 22 are arranged to beconnected to each other in series to (ii) a state where one of theadjacent ones of the plurality of upper structures 22 is rotatable withrespect to the other one of the adjacent ones of the plurality of upperstructures 22 in such a range that the adjacent ones of the plurality ofupper structures 22 form a V shape in a direction opposite to thedirection of gravitational force.

Meanwhile, the adjacent ones of the plurality of upper structures 22 isnot changed from (i) the state where the adjacent ones of the pluralityof upper structures 22 are arranged to be connected to each other inseries to (ii) a state where the adjacent ones of the plurality of upperstructures 22 form a V shape in the direction of gravitational force.

Accordingly, the adjacent ones of the plurality of upper structures 22of the upper structure group 20 engage with each other via their sidesurfaces, so that a surface of the upper structure group 20, whichsurface faces and in contact with a surface of the lower structure group21, becomes a plane surface having no gap. For this reason, it ispossible to (i) prevent an abject from being sandwiched between adjacentones of the plurality of upper structures 22, and (ii) prevent dust fromentering a space between adjacent ones of the plurality of upperstructures 22. Further, it is possible to increase a rigidity of the armsection 2.

Furthermore, a range of rotational movement of the plurality of upperstructures 22 is not limited to the range described above, in a casewhere a reduction in a property of preventing entry of dust and areduction in rigidity are accepted.

Next, the following description deals with an arrangement of each of theplurality of upper structures 22. As illustrated in FIGS. 5 and 6, eachof the plurality of upper structures 22 generally has a plate shape, andhas a through hole 24 a at one of ends of the upper structure 22, andthrough hole 24 b at the other one of ends of the upper structure 22, asdescribed above. In a case where a direction in which adjacent ones ofthe plurality of upper structures 22 are coupled with each other isreferred to as “longitudinal direction” (as described below), a singleupper structure 22 has the through hole 24 a at one of its ends in thelongitudinal direction and the through hole 24 b at the other one of itsends in the longitudinal direction.

Furthermore, it is possible that a bottom surface of each of theplurality of upper structures 22 has a bottom surface convex-concavestructure 22 a, which engages with an upper surface convex-concavestructures 23 c provided on an upper surface of a corresponding one ofthe plurality of lower structures 23 (see FIG. 10). In this case, it ispossible to (i) prevent significantly an upper structure 22 and a lowerstructure 23 from being out of alignment with respect to each other inthe coupling direction and (ii) further increase a rigidity of acombined structure of the upper structure 22 and the lower structure 23.

Note that, in a case where a gear roller is provided, as a pressingroller 42 (later described), on an upper surface of a part where theplurality of upper structures 22 of the upper structure group 20 arearranged to be connected to each other in series in the horizontaldirection, or in a case where an arrangement which is the same as thegear 34 (not illustrated) is provided in place of the pressing roller42, an upper surface convex-concave structure which engages with such agear can be formed on the upper surface of each of the plurality ofupper structures 22.

Drive Means

The drive means 40 has the following functions: (1) forming a combinedstructure of the plurality of upper structures 22 and the plurality oflower structures 23, which structure extends directly and is rigid; and(2) releasing such a direct rigid combined structure. The above (1) isobtained in such a manner that the lower structure group 21, in whichadjacent ones of the plurality of lower structures 23 are in contactwith each other, coupled with each other via their side surfaces 23 b(illustrated in FIGS. 4 and 7), and arranged in the horizontaldirection, is arranged under the upper structure group 20, in whichadjacent ones of the plurality of upper structures 22 are in contactwith each other, coupled with each other via their side surfaces 22 b(illustrated in FIG. 6), and are arranged in the horizontal direction.The above (2) is obtained in such a manner that the upper structuregroup 20 of the direct rigid combined structure of the plurality ofupper structures 22 and the plurality of lower structures 23 is detachedfrom the lower structure group 21 which is provided adjacent to theupper structure group 20.

With such functions, the rigid combined structure of the plurality ofupper structures 22 and the plurality of lower structures 23, connectedin series, is realized as the arm section 2 protruding from an openingsection 10 c′ illustrated in FIG. 7, and can change its length(extension and retraction of the direct acting extensible andretractable joint J3) arbitrarily. Hereinafter, a length of a part ofthe combined structure of the plurality of upper structures 22 and theplurality of lower structures 23, which part protrudes from the openingsection 10 c′, is referred to as “arm length”, in some cases.

The drive means 40 includes drive means 40 a for causing the lowerstructure group 21 to operate, and separation means 40 c (see FIG. 2).

Note that, in place of the arrangement employing the drive means 40 afor causing the lower structure group to operate and the separationmeans 40 c, the drive means 40 can have an arrangement employing drivemeans 40 b (see FIG. 7) for causing the upper structure group 20 tooperate and the separation means 40 c.

Further, in order to cause operations of the upper structure group 20and the lower structure group 21 to be in synchronization with eachother completely, the drive means 40 can include all of the drive means40 a for the lower structure group, the drive means 40 b for the upperstructure group, and the separation means 40 c.

The drive means 40 a for the lower structure group is provided in thevicinity of the opening section 10 c′ of the third supporting section 10c so as to cause the lower structure group 21 to move in an axialdirection. The following description deals with details of the drivemeans 40 a for the lower structure group with reference to FIG. 7. Thedrive means 40 a for the lower structure group includes a gear 34 whichengages with a bottom surface convex-concave structure 23 a of each ofthe plurality of lower structures 23, and a drive mechanism 33 which isconstituted by an actuator 35 for driving the gear 34 (see FIG. 7).

Furthermore, the drive means 40 a for the lower structure group caninclude a pressing roller (pressing member) 41.

The drive means 40 b for the upper structure group is provided in thevicinity of the opening section 10 c′ of the third supporting section 10c so as to cause the upper structure group 20 to move in the axialdirection. The following description deals with details of the drivemeans 40 b for the upper structure group. The drive means 40 b for theupper structure group includes a gear which engages with an uppersurface convex-concave structure of each of the plurality of upperstructures 22, and a drive mechanism which is constituted by an actuatorfor driving the gear. Further, the drive means 40 b for the upperstructure group can include a pressing roller (pressing member) 42.

Note that, in place of the arrangement described above, the drivemechanism 33 can have an arrangement employing (i) a worm gear reducerconstituted by a combination of the bottom surface convex-concavestructure 23 b of each of the plurality of lower structures 23 and aworm gear, and (ii) an actuator for driving the worm gear. Alternately,in place of the arrangement described above, the drive mechanismconstituting the drive means 40 b for the upper structure group can havean arrangement employing (i) a worm gear reducer constituted by acombination of the upper surface convex-concave structure of each of theplurality of upper structures 22 and a worm gear, and (ii) an actuatorfor driving the worm gear. According to such an arrangement, it ispossible to achieve a large gear ratio with the use of gears the numberof which is significantly smaller (several gears) than the number ofgears of a gear reducer employing general spur gears. It is thereforepossible to realize a gear reducer having a significantly compact body.Further, this arrangement has no back drivability. For this reason, thearm section 2 is operated only by the actuator 35, and even if externalforce is provided to operate the arm section 2, the arm section 2 wouldnot be operated.

As illustrated in FIG. 7, the pressing roller (pressing member) 41 ofthe drive means 40 a for the lower structure group is provided to becloser to the opening section 10 c′ of the third supporting section, ascompared with the drive mechanism 33. The pressing roller 41 (i)presses, in a direction opposite to the direction of gravitationalforce, a bottom surface of the lower structure group 21 (lowerstructures 23) which is linearly arranged and is to be outputted by thedrive mechanism 33 from the opening section 10 c′, and (ii) outputs thelower structure group 21 to the outside from the opening section 10 c′.

Furthermore, the pressing roller (pressing member) 42 of the drive means40 b for the upper structure group is also provided to be closer to theopening section 10 c′ of the third supporting section 10 c, as comparedwith the drive mechanism. The pressing roller 42 (i) presses, in thedirection of gravitational force, an upper surface of the upperstructure group 20 (the upper structures 22) which is linearly arrangedand is to be outputted from the opening section 10 c′ by the drivemechanism, and (ii) outputs the upper structure group 20 from theopening section 10 c′ to the outside.

The rigid combined structure of the plurality of upper structures 22 andthe plurality of lower structures 23, i.e., the arm section, isestablished in such a manner that the plurality of upper structures 22and the plurality of lower structures 23 are pressed with respect toeach other (in overlapping directions) by use of the pressing roller 41and the pressing roller 42 and, as a result, are in contact with eachother.

Note that the arm section can be held by the pressing roller 42 and thegear 34 for driving the plurality of lower structures 23.

Further, the arm section can be held by the pressing roller 41 and thegear for driving the plurality of upper structures 22.

Furthermore, the arm section can be held by the gear for driving theplurality of upper structures 22 and the gear 34 for driving theplurality of lower structures 23. Moreover, the arm section can be heldby the pressing roller 41, the pressing roller 42, and the gear 34 fordriving the plurality of lower structures 23.

Further, the arm section can be held by the pressing roller 41, thepressing roller 42, and the gear for driving the plurality of upperstructures 22.

Furthermore, the arm section can be held by the pressing roller 41, thegear for driving the plurality of upper structures 22, and the gear 34for driving the plurality of lower structures 23.

Moreover, the arm section can be held by the pressing roller 42, thegear for driving the plurality of upper structures 22, and the gear 34for driving the plurality of lower structures 23.

A mechanism of each of the pressing roller 41 is not particularlylimited. However, as an example, the pressing roller has an arrangementin which an elastic member such as a spring is additionally attached toa rotational axis of a roller.

Two pressing rollers 41 are provided along the upper structure group 20in FIG. 7. Note, however, that the number of pressing rollers 41 is notlimited to this.

Further, in the present embodiment, as illustrated in FIGS. 2 and 7, thetwo pressing rollers 41 of the drive means 40 a for the lower structuregroup are provided to be closer to the opening section 10 c′, ascompared with the drive mechanism 33 of the drive means 40 a for thelower structure group. Note, however, that the present invention is notlimited to this. The drive mechanism 33 can be provided to be closer tothe opening section 10 c′ than the two pressing rollers 41 are.

Next, the drive means 40 b for the upper structure group is provided inthe vicinity of the opening section 10 c′ of the third supportingsection 10 c, so as to cause the upper structure group 20 to be moved.The drive means 40 b for the upper structure group includes the pressingroller (pressing members) 42. The pressing roller 42 can press the upperstructure group 20 (upper structures 22) in the direction ofgravitational force. A mechanism of the pressing rollers 42 is notparticularly limited. However, as an example, the pressing roller 42 canhave an arrangement in which an elastic member such as a spring isadditionally attached to a rotational axis of a pressing roller.

Three pressing rollers 42 are provided along the upper structure group20 in FIGS. 2 and 7. Note, however, that the number of pressing rollers42 is not limited to this.

Further, in addition to the three pressing rollers 42, it is alsopossible to provide, in a position opposite to an upper surface of theupper structure group 20, a member having the same arrangement as thatof the drive mechanism 33 of the drive means 40 a for the lowerstructure group. In this case, the upper surface of the upper structuregroup 20 has the upper surface convex-concave structure.

The following description deals with, with reference to FIG. 7, (i) howthe upper structure group 20 and the lower structure group 21 arecombined with each other by driving carried out by the drive means 33and (ii) how the direct rigid combined (pressed) structure of theplurality of upper structures 22 and the plurality of lower structures23 is formed.

As described above, the upper structure group 20 is such that theplurality of upper structures 22 are arranged to be connected to eachother in series, and the lower structure group 21 is such that theplurality of lower structures 23 are arranged to be connected to eachother in series. In a case where positions of coupling axes of the upperstructure group 20 and positions of coupling axes of the lower structuregroup 21 correspond to each other in the longitudinal direction (asillustrated in FIGS. 2 and 7), that is, in a case where, in the armsection in which both of the upper structure group 20 and the lowerstructure group 21 are rigid, the coupling axes of the lower structuregroup 21 are positioned below the respective coupling axes of the upperstructure group 20 in the direction of gravitational force, (i) theupper structure group 20 and the lower structure group 21 are supportedin a position close to the opening section 10 c′ of the third supportingsection 10 c, and (ii) one of ends of the upper structure group 20 andone of ends of the lower structure group 21 are connected to a commonblock member 60. It is thus possible to realize such a rigid state ofthe arm section 2.

The present invention is not limited to the arrangement in which thecoupling axes of the lower structure group 21 are positioned below therespective coupling axes of the upper structure group 20 in thedirection of gravitational force. It is also possible to have such anarrangement that each the coupling axes of the plurality of upperstructures 22 is provided in the vicinity of a center of a correspondingone of the plurality of lower structures 23 and each of the couplingaxes of the plurality of lower structures 23 are provided in thevicinity of a center of a corresponding one of the plurality of upperstructures 22 (see FIG. 8), that is, in the arm section in which boththe upper structure group 20 and the lower structure group 21 are rigid,each of the coupling axes of the lower structure group is provided belowa space between adjacent ones of the coupling axes of the upperstructure group 20 in the direction of gravitational force. In thiscase, it is possible to prevent successfully both the plurality of upperstructures 22 of the upper structure group 20 and the plurality of lowerstructures 23 of the lower structure group 21 from being flexed androtated. This makes it possible to cause the combined structure to havea greater rigidity.

(Storage of Arm Section)

Most of the rigid combined structure of the plurality of upperstructures 22 and the plurality of lower structures 23, that is, most ofthe arm section, protrudes from the opening section 10 c′ of the thirdsupporting section 10 c to an outside in the axial direction. Meanwhile,a part of the upper structure group 20 and a part of the lower structuregroup 21, both of which do not constitute the rigid combined structure,are (i) arranged to be curved along a shape of the robot arm supportingmember 1 (see FIG. 1), and are (ii) stored inside inner space of therobot arm supporting member 1.

In order to retract an extended combined structure of the plurality ofupper structures 22 and the plurality of lower structures 23, the gear34 of the drive mechanism 33 is rotated so as to retract the combinedstructure of the plurality of upper structures 22 and the plurality oflower structures 23 into an inside of the third supporting section 10 c.Inside the third supporting section 10 c, the separation means 40 c isprovided at a position sandwiched between the upper structure group 20and the lower structure group 21 (see FIGS. 2 and 7). The combinedstructure of the plurality of upper structures 22 and the plurality oflower structures 23 is retracted into the inner space of the thirdsupporting section 10 c, so that a combined part of the combinedstructure is released by insertion of the separation means 40 c into thecombined part. The combined structure is thus separated into two parts.By further retracting the combined structure of the plurality of upperstructures 22 and the plurality of lower structures 23 into the insideof the third supporting section 10 c, the upper structure group 20 andthe lower structure group 21 are moved from the third supporting section10 c to the second supporting section 10 b, and then are stored in thefirst supporting section 10 a.

In a case where the combined structure of the plurality of upperstructures 22 and the plurality of lower structures 23 is stored, theupper structure group 20 separated by the separation means 40 c is movedabove the separation means 40 c. The upper structure group 20 thusseparated is such that each of the plurality of upper structures 20 canrotate around a pin 30 serving as a rotational axis. Accordingly, theupper structure group 20 is stored in the arm supporting member 1 alonga shape of the arm supporting member 1. The lower structure group 21thus separated is such that each of the plurality of lower structures 21can rotate around a pin serving as a rotational axis. Accordingly, thelower structure group 21 is stored in the arm supporting member 1 alongthe shape of the arm supporting member 1. As such, since both the upperstructure group 20 and the lower structure group 21 can be stored in thearm supporting member 1 along the shape of the arm supporting member 1,it is possible to have a reduction in size of the arm section 2 in acase where the arm section 2 is stored.

(Condition for Rigid Structure of Arm Section)

According to the present embodiment, as illustrated in FIGS. 2 and 7,the rigid structure of the arm section 2 is realized on the followingconditions (i) through (iv): (i) one of ends of the upper structuregroup 20 and one of ends of the lower structure group 21 are connectedto the common block member 60, (ii) a part of the upper structure group20, protruding from the opening section 10 c′ of the third supportingsection 10 c to the outside, and a part of the lower structure group 21,protruding from the opening section 10 c′ to the outside, are kept beingidentical with each other in length all the time, (iii) the lowerstructure group 21 is such that, in a case where the plurality of lowerstructures 23 of lower structure group 21 are arranged to be connectedto each other in series, each of the plurality of lower structures 23can be rotated around a pin 30, serving as a rotational axis, forward inthe direction of gravitational force but cannot be rotated backward, and(iv) the upper structure group 22 is such that, in a case where theplurality of upper structures 22 of the upper structure group 20 arearranged to be connected to each other in series, each of the pluralityof upper structures 22 can be rotated around a pin 31, serving as arotational axis, forward and backward.

In order to realize such a condition that (i) the one of ends of theupper structure group 20 and the one of ends of the lower structuregroup 21 are connected to the common block member 60, and, in thisstate, (ii) the part of the upper structure group 20, protruding fromthe opening section 10 c′ of the third supporting section 10 c to theoutside, and the part of the lower structure group 21, protruding fromthe opening section 10 c′ to the outside, are kept being identical witheach other in length, it is necessary to cause the operation of theupper structure group 20, driven by the drive means 40 b for the upperstructure group, and the operation of the lower structure group, drivenby the drive means 40 a for the lower structure group, to be insynchronization with each other.

Further, it is possible that (i) the operation of the upper structuregroup 20 is controlled by the drive means 40 b for driving the upperstructure group 20, and (ii) the operation of the lower structure group21 is controlled by an engaged structure of the bottom surfaceconvex-concave structure 22 a of each of the plurality of upperstructures 22 and the upper surface convex-concave structure 23 c of theeach of the plurality of lower structures 23.

Furthermore, it is possible that (i) the operation of the lowerstructure group 21 is controlled by the drive means 40 a for driving thelower structure group 21, and (ii) the operation of the upper structuregroup 22 is controlled by an engaged structure of the bottom surfaceconvex-concave structure 22 a of each of the plurality of upperstructures 22 and the upper surface convex-concave structure 23 c ofeach of the plurality of lower structures 23.

Moreover, it is also possible that (i) the operation of the upperstructure group 20 is controlled by the drive means 40 b for driving theupper structure group 20, and (ii) the operation of the lower structuregroup 21 is not controlled by the drive means 40 a for driving the lowerstructure group 21 but the engaged structure of the bottom surfaceconvex-concave structure 23 a of each of the plurality of upperstructures 22 and the upper surface convex-concave structure 23 c ofeach of the plurality of lower structures 23.

Further, it is possible that (i) the operation of the upper structuregroup 20 is not controlled by the drive means 40 b for driving the upperstructure group 20, and (ii) the operation of the lower structure group21 is controlled by the drive means 40 a for driving the lower structuregroup 21, and (iii) the operation of the lower structure group 21 iscontrolled by the engaged structure of the bottom surface convex-concavestructure 22 a of each of the plurality of upper structures 22 and theupper surface convex-concave structure 23 c of each of the plurality oflower structures 23.

Furthermore, it is also possible that, in order to have an increase inrigidity of the arm section 2, (i) the operation of the upper structuregroup 20, driven by the drive means 40 b for the upper structure group,and the operation of the lower structure group 22, driven by the drivemeans 40 a for the lower structure group, are caused to be insynchronization with each other, and (ii) the operation of the upperstructure group 22 is controlled by the engaged structure of the bottomsurface convex-concave structure 22 a of each of the plurality of upperstructures 22 and the upper surface convex-concave structure 23 c ofeach of the plurality of lower structures 23.

(Modified Example of Arm Section)

In the present embodiment, the direct acting extensible and retractablearm joint J3 is constituted by the upper structure group 20 and thelower structure group 21 (see FIG. 2). Note, however, that the presentinvention is not limited to this. The present invention can have eitheran arrangement illustrated in FIG. 11 or an arrangement illustrated inFIG. 13. The following description deals with the arrangementillustrated in FIG. 11 and the arrangement illustrated in FIG. 13.

The arrangement illustrated in FIG. 11 is different from the arrangementillustrated in FIG. 2 in that the upper structure group 21 of the directacting extensible and retractable arm joint J3 illustrated in FIG. 2 isreplaced with a different structure. Specifically, a lower structure 28(see FIG. 12) is substantially similar to the lower structure 23illustrated in FIG. 2 but the upper structure 22 illustrated in FIG. 2,having substantially a plate structure, is replaced with an upperstructure 27 (see FIG. 12) having a block structure.

The arrangement illustrated in FIG. 11 is such that (i) the lowerstructure group constituted by a plurality of lower structures 28 issuch that, in a case where the plurality of lower structures 28 of thelower structure group are arranged to be connected to each other inseries, each of the plurality of lower structures 28 can be rotatedaround a pin, serving as a rotational axis, forward in the direction ofgravitational force but cannot be rotated backward, and (ii) the upperstructure group constituted by a plurality of upper structures 27 issuch that, in a case where the plurality of upper structures 27 of theupper structure group are arranged to be connected to each other inseries, each of the plurality of upper structures 27 can be rotatedaround a pin, serving as a rotational axis, either forward and backwardin the direction of gravitational force or not backward but only forwardin the direction of gravitational force.

FIG. 13 illustrates an arrangement in which the arrangement of theplurality of upper structures 22 and the arrangement of the plurality oflower structures 23, illustrated in FIG. 2, are reversed in anup-and-down direction. Each of the plurality of upper structures 22illustrated in FIG. 2 has substantially a plate structure, whereas eachof a plurality of upper structures illustrated in FIG. 13 has a blockstructure which is similar to that of the upper structure 27 illustratedin FIG. 12. Each of the plurality of lower structures 23 illustrated inFIG. 2 has a block structure, whereas each of a plurality of lowerstructures illustrated in FIG. 13 has a substantially a plate structure.The arrangement illustrated in FIG. 13 is such that (i) a lowerstructure group constituted by the plurality of lower structures is suchthat, in a case where the plurality of lower structures of the lowerstructure group are arranged to be connected to each other in series,each of the plurality of lower structures can be rotated around a pin,serving as a rotational axis, forward in the direction of gravitationalforce, but cannot be rotated backward, and (ii) an upper structure groupconstituted by the plurality of upper structures is such that, in a casewhere the plurality of upper structures of the upper structure group arearranged to be connected to each other in series, each of the pluralityof upper structures can be rotated around a pin either (i) forward andbackward in the direction of gravitational force or (ii) not backwardbut only forward in the direction of gravitational force.

As illustrated in FIGS. 11 and 13, the upper structure group and thelower structure group, arranged in parallel with each other in thehorizontal direction, (i) can be coupled with each other by use of thesame mechanism as that of the drive means 40 described above so as tohave a rigid structure, (ii) can release such a coupling structure, andtherefore (iii) can have the same effects as those of the arrangementillustrated in FIG. 2. Note that, either in the arrangement illustratedin FIG. 11 or in the arrangement illustrated in FIG. 13, (i) the drivemeans 40 illustrated in FIG. 2 can be provided either below the lowerstructure group or above the upper structure group, or, alternatively,(ii) the drive means 40 can be provided blow the lower structure group,and at the same time, another drive means 40 can be provided above theupper structure group.

In other words, as illustrated in FIGS. 11, 12, and 13, the directacting extensible and retractable arm joint J3 of the present inventionis formed in such a manner that the upper structure group and the lowerstructure group overlap each other to have a rigid structure.

Further, the inside of the direct acting extensible and retractable armjoint J3 is a hollowed structure, and a wiring line can be providedinside the direct acting extensible and retractable arm joint J3. Note,however, that the present invention is not limited to this. It ispossible that the direct acting extensible and retractable arm joint J3does not have such a hollowed structure, and the wiring line cannot beprovided inside the direct acting extensible and retractable arm jointJ3. That is, direct acting extensible and retractable arm joint J3 canhave an arrangement in which the upper structure group and/or the lowerstructure group have an arrangement in which a plurality of structures,each having neither a concave shape nor a hollowed shape, are connectedto each other in series.

The arrangement of the present invention is thus described. Note,however, that the present embodiment is merely an example of the presentinvention. The present invention is not limited to the scope of thedescription of the present embodiment, and various alterations and/orsubstitutions can be carried out by a skilled person within the scope ofclaims.

(Effects of the Present Embodiment)

By using the robot arm 50 of the present embodiment, having thearrangement described above, it is possible to carry out extension andretraction of the arm of the arm section, without using a bending jointlink. For this reason, it is possible to prevent an object from beingsandwiched between arms due to rotation of a rotational joint providedbetween the arms. This effect is a significant advantage for a welfarerobot arm for supporting an operation in a daily life in place of humanpower. Further, particularly, according to the robot arm of the presentembodiment, the extension and retraction of the arm is realized by useof only the direct acting extensible and retractable arm. Accordingly,in a case where the robot arm of the present embodiment is provided at awheel chair or in the vicinity of a bed, as a welfare robot arm, it ispossible to minimize a range in which a user's visibility is limited, ascompared with the arrangement employing the bending joint link betweenthe arms. Furthermore, an extension/retraction move of the robot arm ofthe present embodiment is simple and minimum in front of the user. It istherefore possible to reduce visual discomfort of the user, as comparedwith the arrangement employing the bending joint link between the arms.

The inventors of the present invention have focused on such a situationthat, generally, in a case where a handicapped person uses a robot armas an assistant robot or a welfare robot, saliva of the user or foodparticles are likely to adhere to the robot arm. In such a situation,since the arrangement employing the bending joint link has, on asurface, a lot of gaps between links, it is likely that a finger isaccidentally withdrawn to the inside of the direct acting extensible andretractable arm mechanism or an object (a foreign matter or dust)adhering to the arm section enters the inside of the direct actingextensible and retractable arm mechanism. This might cause constituentsof the direct acting extensible and retractable arm mechanism not towork smoothly in combination with each other, and, as a result, it mightbecome impossible to cause the direct acting extensible and retractablearm mechanism to be in operation normally. On the other hand, accordingto the arrangement of the present invention, the upper surface of thearm section is a plane surface having no gap. Accordingly, there is norisk that a normal operation of the direct acting extensible andretractable arm mechanism is prevented. It is thus possible to realize arobot arm which has a high reliability in its operation.

Modified Example 1 of the Present Embodiment

As a matter of course, the extensible and retractable arm mechanism canbe altered variously. For example, shapes of the upper structure 22 andthe lower structure 23, or a method of causing the arm section 2 to havea rigid structure can be changed.

For example, a length of the upper structure 22 in the longitudinaldirection can be shorter than a length of the lower structure 23 in thelongitudinal direction, as illustrated in FIG. 14.

Alternatively, the length of the upper structure 22 in the longitudinaldirection can be longer than the length of the lower structure 23 in thelongitudinal direction, as illustrated in FIG. 15.

The lower structure group 21 is such that adjacent ones of the pluralityof lower structures are coupled with each other via only a pin 30. Forthis reason, it is possible that, in a case where (i) adjacent ones ofthe plurality of lower structures 23 are arranged to be connected toeach other in series such that their concave opening sections face inthe same direction, the adjacent ones of the plurality of lowerstructures 23 can be rotated so that their opening sections face outwardto form a V shape. However, as illustrated in FIG. 16, it is possible tohave such an arrangement that (i) each of the plurality of lowerstructures 23 includes lock mechanisms 23 e and 23 f, (ii) when the armsection is outputted from the opening section 10 c′ illustrated in FIG.7, a lock mechanism 23 e of one of adjacent ones of the plurality oflower structures 23 and a lock mechanism 23 f of the other one ofadjacent ones of the plurality of lower structures 23 are connected toeach other so that the adjacent ones of the plurality of lowerstructures 23 are fixed and cannot be rotated, and (iii) when the armsection is stored in the robot arm supporting member 1 via the openingsection 10 c′, the lock mechanism 23 e and the lock mechanism 23 f arereleased from each other so that the adjacent ones of the plurality oflower structures 23 are separated from each other and each of theadjacent ones of the plurality of lower structures 23 can be rotatedaround a corresponding pin 30 serving as a rotational axis.

Modified Example 2 of the Present Embodiment)

According to the present embodiment, as illustrated in FIG. 7, (i) thedrive means 40 a for the lower structure group includes the drivemechanism 33 that is constituted by (a) the gear 34 which engages withthe bottom surface convex-concave structure 23 a of each of theplurality of lower structures 23, and (b) the actuator 35 for drivingthe gear 34, and the drive means 40 a is provided below each of theplurality of lower structures 23, (ii) the drive means 40 b for theupper structure group includes the drive mechanism that is constitutedby (a) the gear which engages with the upper convex-concave structure ofeach of the plurality of upper structures 22 and (b) the actuator fordriving the gear, and the drive means 40 b is provided above each of theplurality of upper structures 22, and (iii) the driving is carried outby use of at least one of the drive means 40 a and the drive means 40 b.Note, however, that the present invention is not limited to this, andthe drive means can be provided either (1) on a left side of the upperstructure group and/or the lower structure group, or (2) on a right sideof the upper structure group and/or the lower structure group.

Modified Example 2-(a)

First, the following description deals with Modified Example 2-(a). (a)of FIG. 17 is a perspective view illustrating the upper surface of thethird supporting section 10 c (the upper structures 22). (a) of FIG. 17illustrates a region in the vicinity of the opening section 10 c′ of thethird supporting section 10 c. Here, the plurality of upper structures22 are connected to each other in series to have a rigid structure insuch a manner that the plurality of upper structures 22 are connected tothe respective plurality of lower structures 23 of the lower structuregroup (a deep side in (a) of FIG. 17). According to Modified Example2-(a), at least the gear 34 is provided on the right side with respectto an extensible and retractable direction of the arm constituted by theplurality of upper structures 22 and the plurality of lower structures23. As illustrated in (b) of FIG. 17, the gear 34 is formed so as to bein contact with both the plurality of upper structures 22 and theplurality of lower structures 23. It is possible that in not only thegear 34 but also the drive mechanism including the actuator for drivingthe gear 34 is also provided on the right side of the arm sectionconstituted by the plurality of upper structures 22 and the plurality oflower structures 23.

According to Modified Example 2-(a), it is preferable that aconcave-convex structure which engages with the gear 34 is formed both(i) on a right surface of each of the plurality of upper structures 22and (ii) on a right surface of each of the plurality of lower structures23.

Further, in the same manner as the arrangement illustrated in FIG. 7,the pressing rollers 41 are provided, respectively, on the right side ofthe plurality of upper structures 22 and the plurality of lowerstructures 23 and on the left side of the plurality of upper structures22 and the plurality of lower structures 23. The pressing rollers 41,provided, respectively, on the right side and on the left side, can bein contact with both the plurality of upper structures 22 and theplurality of lower structures 23. Alternatively, the pressing rollers 41can be in contact with one of (i) the plurality of upper structures 22and (ii) the plurality of lower structures 23.

Modified Example 2-(b)

Modified Example 2-(b) is such that the drive mechanism of ModifiedExample 2-(a) described above, constituted by the gear 34 and theactuator for driving the gear 34, is provided on the left side of theplurality of upper structures 22 and the plurality of lower structures23.

Modified Example 2-(c)

According to Modified Example 2-(a) described above, the gear 34 isprovided on the right side of the plurality of upper structures 22 theplurality of lower structures 23, so as to cause both the plurality ofupper structures 22 and the plurality of lower structures 23 to bemoved. Meanwhile, Modified Example 2-(c) is such that the gear 34, whichis in contact with (engages with) the plurality of upper structures 22,is provided on the right side of the plurality of upper structures 22,and another gear 34, which is in contact with (engages with) theplurality of lower structures 23, is provided on the left side of theplurality of lower structures 23.

According to the arrangement, it is also possible to realize successfuldriving, in the same manner as the embodiment described above.

Modified Example 2-(d)

Modified Example 2-(d) is such that the positions of the gear 34 and theanother gear 34, described in Modified Example 2-(c), are replaced witheach other, that is, the gear 34, which is in contact with (engageswith) the plurality of upper structures 22, is provided on the left sideof the plurality of upper structures 22, and the another gear 34, whichis in contact with (engages with) the plurality of lower structures 23,is provided on the right side of the plurality of lower structures 23.

Modified Example 2-(e)

Modified Example 2-(e) is such that (i) the gear provided on the rightside of the plurality of upper structures 22 is in contact with (engageswith) the plurality of upper structures 22, so as to drive both theplurality of upper structures 22 and the plurality of lower structures23, or (ii) the gear provided on the right side of the plurality oflower structures 23 is in contact with (engages with) the plurality oflower structures 23, so as to drive both the plurality of lowerstructures and the plurality of upper structures 22.

Alternatively, Modified Example 2-(e) is such that (i) the gear providedon the left side of the plurality of upper structures 22 is in contactwith (engages with) the plurality of upper structures 22, so as to driveboth the plurality of upper structures 22 and the plurality of lowerstructures 23, or (ii) the gear provided on the right side of theplurality of lower structures 23 is in contact with (engages with) theplurality of lower structures 23, so as to drive both the plurality oflower structures 23 and the plurality of upper structures 22.

Modified Example 2-(f)

Modified Example 2-(f) is such that, in addition to the upper gear 34and the lower gear 34 of Modified Example 2-(a), provided on the rightside, another upper gear 34 and another lower gear 34 are furtherprovided on the left side.

According to Modified Examples 2-(a) through 2-(f), the gear 34 and thedrive mechanism are provided at least one of (i) on the left side of thearm section and (ii) on the right side of the arm section. With thearrangement, it is possible to avoid an influence of gravitationalforce, as compared with the arrangement in which the gear 34 and thedrive mechanism are provided at an upper position and a lower position,respectively. Specifically, in a case where the gear 34 and the drivemechanism are provided at the upper position and lower position,respectively, as illustrated in FIG. 7, there is an influence, such asforce and torque, on the drive means due to gravitational force(gravitational force related to the arm section). This might cause anincrease in driving torque and an increase in abrasion. However, witheach of the arrangements of Modified Examples 2-(a) through 2-(f), it ispossible to avoid these problems.

Further, according to Modified Example 2-(f), it is possible to carryout driving while maintaining a balance of the arm section withhorizontally-symmetric force by avoiding a situation that (i) drivingforce is generated from only one side, (ii) and the other side issupported by a roller, and, as a result, (iii) horizontally-symmetricforce is cannot be obtained.

Modified Example 3 of the Present Embodiment

With the drive means illustrated in FIG. 7 or 17, there is a risk that atooth plane might be added to a surface of the direct acting mechanism,and entry of a foreign matter might not be prevented completely.Further, there is also a risk that the tooth plane might be in contactwith a human or an object in the vicinity of the direct actingmechanism. In view of these, it is possible to have such an arrangementthat the tooth plane is deleted from the surface of the direct actingmechanism, so as to avoid the entry of a foreign matter. Further, inorder to eliminate the risk that the tooth plane is in contact with ahuman or an object in the vicinity of the direct acting mechanism, it ispossible to provide the gear 34 between the upper structure group 20 andthe lower structure group 21, as illustrated in FIG. 18. That is, thetooth plane is added to a bottom section of each of the plurality ofupper structures 22 (a surface which faces the plurality of lowerstructures 23), and the tooth plane is driven by the drive means. Withthe arrangement, it is possible to cause both the upper structure groupand the lower structure group to be in operation. The tooth plane of thebottom section of each of the plurality of upper structures 22 can alsobe used to engage with a corresponding one of the plurality of lowerstructures. 23.

It is necessary that, before the upper structure group 20 is in contactwith the gear 34, the upper structure group 20 is arranged linearly(maintained horizontally) by use of a roller. For this reason, a firstroller is provided in the upstream with respect to the gear, a secondroller is provided in the downstream with respect to the gear, and athird roller is provided above the gear. The drive means is located on abackside with respect to the opening section 10 c′ of the thirdsupporting section 10 c. Accordingly, it becomes possible to cause theopening section 10 c′ to have a small size. Further, since gravitationalforce does not have an influence on the drive means, it is possible tohave a reduction in driving torque and a reduction in abrasion.

The present invention is not limited to the description of theembodiments above, but may be altered by a skilled person within thescope of the claims. An embodiment based on a proper combination oftechnical means disclosed in different embodiments is encompassed in thetechnical scope of the present invention. The embodiments and concreteexamples of implementation discussed in the foregoing detailedexplanation serve solely to illustrate the technical details of thepresent invention, which should not be narrowly interpreted within thelimits of such embodiments and concrete examples, but rather may beapplied in many variations within the spirit of the present invention,provided such variations do not exceed the scope of the patent claimsset forth below.

CONCLUSION OF THE PRESENT INVENTION

As described above, a direct acting extensible and retractable armmechanism of the present invention includes: a robot arm supportingmember; a robot arm supporting member; and an arm section beingextensible and retractable directly from one of ends of the robot armsupporting member, the arm section being such that a hand section isattachable to one of ends of the arm section, the arm section beingconstituted by (i) a first structure group in which a plurality of firststructures are coupled with each other in series in such a manner thatadjacent ones of the plurality of first structures are coupled with eachother via a corresponding one of a plurality of first coupling axes in adirection which is orthogonal to a direction of the corresponding one ofthe plurality of first coupling axes and (ii) a second structure groupin which a plurality of second structures are coupled with each other inseries in such a manner that adjacent ones of the plurality of secondstructures are coupled with each other via a corresponding one of aplurality of second coupling axes in a direction which is orthogonal toa direction of the corresponding one of the plurality of second couplingaxes, the plurality of first structures being identical with each otherin width in a direction parallel to the plurality of first couplingaxes, the plurality of second structures being identical with each otherin width in a direction parallel to the plurality of second couplingaxes, the first structure group and the second structure group beingcoupled with each other in such a manner that one of two end firststructures of the plurality of first structures, on a hand section side,and one of two end second structures of the plurality of secondstructures, on the hand section side, are coupled with each other, therobot arm supporting member including, at one of ends of the robot armsupporting member, drive means for (i) pressing the first structuregroup and the second structure group so that the first structure groupand the second structure group become closer to each other and become incontact with each other, (ii) causing the first structure group and thesecond structure group to overlap each other so that a surface of thefirst structure group and a surface of the second structure group, whichsurfaces are in contact with each other, do not slip with respect toeach other, and (iii) driving the first structure group and the secondstructure group in a direction in which the arm section is extensible,in a case where the drive means causes the first structure group and thesecond structure group to overlap each other, the first structure groupand the second structure group forming such a rigid arm section thatrotation of each of the plurality of first structures via thecorresponding one of the plurality of first coupling axes and rotationof each of the plurality of second structures via the corresponding oneof the plurality of second coupling axes are prevented, at least one ofthe first structure group and the second structure group is such thatadjacent ones of structures engage with each other via their sidesurfaces, and form a plane surface having no gap, which plane surfacefaces and is in contact with a surface of the other one of the firststructure group and the second structure group, the robot arm supportingmember including separation means in the robot arm supporting member, ina case where the drive means carries out reverse driving, the separationmeans causes the first structure group and the second structure group tobe separated from each other so that (i) each of the plurality of firststructures is rotatable around the corresponding one of the plurality offirst coupling axes and (ii) each of the plurality of second structuresis rotatable around the corresponding one of the plurality of secondcoupling axes.

Further, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that in a case where (i) the drive means causes the firststructure group and the second structure group to overlap each other andtherefore (ii) the arm section becomes rigid in such a manner that therotation of each of the plurality of first structures via thecorresponding one of the plurality of first coupling axes and therotation of each of the plurality of second structures via thecorresponding one of the plurality of second coupling axes areprevented, and one of the first structure group and the second structuregroup is provided above the other one of the first structure group andthe second structure group, the one of the first structure group and thesecond structure group is such that adjacent ones of structures engagewith each other via their side surfaces and forms a plane surface havingno gap, which plane surface is opposite to a surface that is in contactwith a surface of the other one of the first structure group and thesecond structure group.

Furthermore, in addition to the arrangement, the direct actingextensible and retractable arm mechanism of the present invention ispreferably arranged such that the first structure group is such thatadjacent ones of the plurality of first structures engage with eachother via their side surfaces and form a plane surface having no gap,which plane surface is opposite to a surface that is in contact with asurface of the second structure group, and the second structure group issuch that adjacent ones of the plurality of second structures engagewith each other via their side surfaces and form a plane surface havingno gap, which plane surface is opposite to the surface that is incontact with the surface of the first structure group.

Moreover, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that the one of two end first structures of the pluralityof first structures and the one of two end second structures of theplurality of second structures are physically attached to each other orphysically welded with respect to each other.

Further, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that the one of two end first structures of the pluralityof first structures and the one of two end second structures of theplurality of second structures are combined with a common block.

Furthermore, in addition to the arrangement, the direct actingextensible and retractable arm mechanism of the present inventionpreferably further includes: a pressing member for supporting saidpressing of the first structure group and the second structure group,the pressing member pressing at least one of the first structure groupand the second structure group.

Moreover, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that the drive means is such that (i) the drive meansincludes a drive mechanism constituted by a gear(s) and an actuator forrotating the gear(s), and the gear(s) is in contact with one of thefirst structure group and the second structure group so as to drive boththe first structure group and the second structure group, or (ii) thedrive means includes two drive mechanisms each being constituted by agear(s) and an actuator for rotating the gear(s), and the gear(s) of oneof the two drive mechanisms is in contact with one of the firststructure group and the second structure group and the gear(s) of theother one of the two drive mechanisms is in contact with the other oneof the first structure group and the second structure group, so as todrive both the first structure group and the second structure group.

Further, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that the gear is provided between the first structuregroup and the second structure group.

Furthermore, in addition to the arrangement, the direct actingextensible and retractable arm mechanism of the present invention ispreferably arranged such that a length from a surface of each of theplurality of first structures constituting the first structure group,which surface is in contact with the second structure group, to anopposite surface of each of the plurality of first structure, and alength from a surface of each of the plurality of second structuresconstituting the second structure group, which surface is in contactwith the first structure group, to an opposite surface of each of theplurality of second structures, are identical with each other ordifferent from each other.

Moreover, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that, in a case where (i) the drive means causes the firststructure group and the second structure group to overlap each other andtherefore (ii) the arm section becomes rigid in such a manner that therotation of each of the plurality of first structures via thecorresponding one of the plurality of first coupling axes and therotation of each of the plurality of second structures via thecorresponding one of the plurality of second coupling axes areprevented, one of the first structure group and the second structuregroup is provided above the other one of the first structure group andthe second structure group, and a plurality of coupling axes of theother one of the first structure group and the second structure groupare located below a plurality of coupling axes of the one of the firststructure group and the second structure group in a direction ofgravitational force.

Further, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that, in a case where (i) the drive means causes the firststructure group and the second structure group to overlap each other andtherefore (ii) the arm section becomes rigid in such a manner that therotation of each of the plurality of first structures via thecorresponding one of the plurality of first coupling axes and therotation of each of the plurality of second structures via thecorresponding one of the plurality of second coupling axes areprevented, one of the first structure group and the second structuregroup is provided above the other one of the first structure group andthe second structure group, and each of a plurality of coupling axes ofthe other one of the first structure group and the second structuregroup is located below a region between adjacent ones of a plurality ofcoupling axes of the one of the first structure group and the secondstructure group in a direction of gravitational force.

Furthermore, in addition to the arrangement, the direct actingextensible and retractable arm mechanism of the present invention ispreferably arranged such that a surface of the first structure group anda surface of the second structure group, which surfaces are in contactwith each other, have, respectively, gear sections which engage witheach other.

Moreover, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that each of a plurality of structures constituting one ofthe first structure group and the second structure group has a pluralityof gear sections on its surface which is in contact with a surface ofthe other one of the first structure group and the second structuregroup, and the plurality of gear sections engage with both gear sectionsof adjacent ones of a plurality of structures of the other one of thefirst structure group and the second structure group.

Further, in addition to the arrangement, the direct acting extensibleand retractable arm mechanism of the present invention is preferablyarranged such that the robot arm supporting member is capable ofstoring, inside the robot arm supporting member, the first structuregroup and the second structure group which have been separated from eachother by the separation means, and the first structure group and thesecond structure group, separated from each other by the separationmeans, are stored along an inner shape of the robot arm supportingmember by (i) the rotation of each of the plurality of first structuresvia the corresponding one of the plurality of first coupling axes and(ii) the rotation of each of the plurality of second structures via thecorresponding one of the plurality of second coupling axes.

INDUSTRIAL APPLICABILITY

A robot arm of the present invention includes an arm section constitutedby a direct acting extensible and retractable arm mechanism including aplurality of upper structures, a plurality of lower structures, anddrive means. Accordingly, with the robot arm, it is possible to (i)prevent significantly a finger from being sandwiched in the robot arm orprevent significantly dust from entering the robot arm, and (ii), bystoring the direct acting extensible and retractable arm mechanism in arobot arm supporting member, realize a reduction in a space necessaryfor the robot arm.

Accordingly, for example, the robot arm of the present invention can beused by a handicapped person as a support robot or a welfare robot, andis also used as a robot arm for producing a next-generation robot armfor cellular manufacturing, which operates in the vicinity of a human incooperation with the human.

REFERENCE SIGNS LIST

-   1. Robot arm supporting member (base)-   2. Arm section-   3. Hand section (end effector)-   10 a: First supporting section-   10 b: Second supporting section-   10 c: Third supporting section-   10 c′: Opening section-   20: Upper structure group-   21: Lower structure group-   22: Upper structure-   22 a: Bottom surface convex-concave structure (alignment section)-   22 b: Side surface-   23: Lower structure-   23 a: Side surface convex-concave structure (engaging section)-   23 b: Side surface-   23 c: Upper surface convex-concave structure-   23 d: Bottom surface convex-concave structure-   23 e: Lock mechanism-   23 f: Lock mechanism-   24 a: Through hole-   24 b: Through hole-   25 a: Through hole-   25 b: Through hole-   27: Upper structure-   28: Lower structure-   30: Pin-   31: Pin-   33: Drive mechanism-   34: Gear-   35: Actuator-   40: Drive means (drive mechanism)-   40 a: Drive means for lower structure group-   40 b: Drive means for upper structure group-   40 c: Separation means-   41: Pressing roller (pressing member)-   42: Pressing roller (pressing member)-   50: Robot arm (direct acting extensible and retractable arm    mechanism)-   60: Common block member-   70: First finger-   71: Second finger-   72: Two-finger hand-   G: Installation surface-   J1: First rotational joint (rotational joint means)-   J2: Second rotational joint-   J3: Direct Acting extensible and retractable arm joint (combined    structure of upper structures and lower structures)-   J4: Fourth rotational joint-   J5: Fifth rotational joint-   J6: Sixth rotational joint-   J7: Seventh rotational joint

1. A direct acting extensible and retractable arm mechanism comprising:a robot arm supporting member; and an arm section being extensible andretractable directly from one of ends of the robot arm supportingmember, the arm section being such that a hand section is attachable toone of ends of the arm section, the arm section being constituted by (i)a first structure group in which a plurality of first structures arecoupled with each other in series in such a manner that adjacent ones ofthe plurality of first structures are coupled with each other via acorresponding one of a plurality of first coupling axes in a directionwhich is orthogonal to a direction of the corresponding one of theplurality of first coupling axes and (ii) a second structure group inwhich a plurality of second structures are coupled with each other inseries in such a manner that adjacent ones of the plurality of secondstructures are coupled with each other via a corresponding one of aplurality of second coupling axes in a direction which is orthogonal toa direction of the corresponding one of the plurality of second couplingaxes, the plurality of first structures being identical with each otherin width in a direction parallel to the plurality of first couplingaxes, the plurality of second structures being identical with each otherin width in a direction parallel to the plurality of second couplingaxes, the first structure group and the second structure group beingcoupled with each other in such a manner that one of two end firststructures of the plurality of first structures, on a hand section side,and one of two end second structures of the plurality of secondstructures, on the hand section side, are coupled with each other, therobot arm supporting member including drive means for (i) pressing thefirst structure group and the second structure group so that the firststructure group and the second structure group become closer to eachother and become in contact with each other, (ii) causing the firststructure group and the second structure group to overlap each other sothat a surface of the first structure group and a surface of the secondstructure group, which surfaces are in contact with each other, do notslip with respect to each other, and (iii) driving the first structuregroup and the second structure group in a direction in which the armsection is extensible, in a case where the drive means causes the firststructure group and the second structure group to overlap each other,the first structure group and the second structure group forming such arigid arm section that rotation of each of the plurality of firststructures via the corresponding one of the plurality of first couplingaxes and rotation of each of the plurality of second structures via thecorresponding one of the plurality of second coupling axes areprevented, at least one of the first structure group and the secondstructure group is such that adjacent ones of structures engage witheach other via their side surfaces, and form a plane surface having nogap, which plane surface faces and is in contact with a surface of theother one of the first structure group and the second structure group,the robot arm supporting member including separation means in the robotarm supporting member, in a case where the drive means carries outreverse driving, the separation means causes the first structure groupand the second structure group to be separated from each other so that(i) each of the plurality of first structures is rotatable around thecorresponding one of the plurality of first coupling axes and (ii) eachof the plurality of second structures is rotatable around thecorresponding one of the plurality of second coupling axes.
 2. Thedirect acting extensible and retractable arm mechanism as set forth inclaim 1, wherein: in a case where (i) the drive means causes the firststructure group and the second structure group to overlap each other andtherefore (ii) the arm section becomes rigid in such a manner that therotation of each of the plurality of first structures via thecorresponding one of the plurality of first coupling axes and therotation of each of the plurality of second structures via thecorresponding one of the plurality of second coupling axes areprevented, one of the first structure group and the second structuregroup is provided above the other one of the first structure group andthe second structure group; and the one of the first structure group andthe second structure group is such that adjacent ones of structuresengage with each other via their side surfaces and forms a plane surfacehaving no gap, which plane surface is opposite to a surface that is incontact with a surface of the other one of the first structure group andthe second structure group.
 3. The direct acting extensible andretractable arm mechanism as set forth in claim 1, wherein: the firststructure group is such that adjacent ones of the plurality of firststructures engage with each other via their side surfaces and form aplane surface having no gap, which plane surface is opposite to asurface that is in contact with a surface of the second structure group;and the second structure group is such that adjacent ones of theplurality of second structures engage with each other via their sidesurfaces and form a plane surface having no gap, which plane surface isopposite to the surface that is in contact with the surface of the firststructure group.
 4. The direct acting extensible and retractable armmechanism as set forth in claim 1, wherein: the one of two end firststructures of the plurality of first structures and the one of two endsecond structures of the plurality of second structures are physicallyattached to each other or physically welded with respect to each other.5. The direct acting extensible and retractable arm mechanism as setforth in claim 1, wherein: the one of two end first structures of theplurality of first structures and the one of two end second structuresof the plurality of second structures are combined with a common block.6. The direct acting extensible and retractable arm mechanism as setforth in claim 1, further comprising: a pressing member for supportingsaid pressing of the first structure group and the second structuregroup, the pressing member pressing at least one of the first structuregroup and the second structure group.
 7. The direct acting extensibleand retractable arm mechanism as set forth in claim 1, wherein: thedrive means is such that (i) the drive means includes a drive mechanismconstituted by a gear(s) and an actuator for rotating the gear(s), andthe gear(s) is in contact with one of the first structure group and thesecond structure group so as to drive both the first structure group andthe second structure group, or (ii) the drive means includes two drivemechanisms each being constituted by a gear(s) and an actuator forrotating the gear(s), and the gear(s) of one of the two drive mechanismsis in contact with one of the first structure group and the secondstructure group and the gear(s) of the other one of the two drivemechanisms is in contact with the other one of the first structure groupand the second structure group, so as to drive both the first structuregroup and the second structure group.
 8. The direct acting extensibleand retractable arm mechanism as set forth in claim 7, wherein: the gearis provided between the first structure group and the second structuregroup.
 9. The direct acting extensible and retractable arm mechanism asset forth in claim 1, wherein: a length from a surface of each of theplurality of first structures constituting the first structure group,which surface is in contact with the second structure group, to anopposite surface of each of the plurality of first structure, and alength from a surface of each of the plurality of second structuresconstituting the second structure group, which surface is in contactwith the first structure group, to an opposite surface of each of theplurality of second structures, are identical with each other ordifferent from each other.
 10. The direct acting extensible andretractable arm mechanism as set forth in claim 1, wherein: in a casewhere (i) the drive means causes the first structure group and thesecond structure group to overlap each other and therefore (ii) the armsection becomes rigid in such a manner that the rotation of each of theplurality of first structures via the corresponding one of the pluralityof first coupling axes and the rotation of each of the plurality ofsecond structures via the corresponding one of the plurality of secondcoupling axes are prevented, one of the first structure group and thesecond structure group is provided above the other one of the firststructure group and the second structure group; and a plurality ofcoupling axes of the other one of the first structure group and thesecond structure group are located below a plurality of coupling axes ofthe one of the first structure group and the second structure group in adirection of gravitational force.
 11. The direct acting extensible andretractable arm mechanism as set forth in claim 1, wherein: in a casewhere (i) the drive means causes the first structure group and thesecond structure group to overlap each other and therefore (ii) the armsection becomes rigid in such a manner that the rotation of each of theplurality of first structures via the corresponding one of the pluralityof first coupling axes and the rotation of each of the plurality ofsecond structures via the corresponding one of the plurality of secondcoupling axes are prevented, one of the first structure group and thesecond structure group is provided above the other one of the firststructure group and the second structure group; and each of a pluralityof coupling axes of the other one of the first structure group and thesecond structure group is located below a region between adjacent onesof a plurality of coupling axes of the one of the first structure groupand the second structure group in a direction of gravitational force.12. The direct acting extensible and retractable arm mechanism as setforth in claim 1, wherein: a surface of the first structure group and asurface of the second structure group, which surfaces are in contactwith each other, have, respectively, gear sections which engage witheach other.
 13. The direct acting extensible and retractable armmechanism as set forth in claim 12, wherein: each of a plurality ofstructures constituting one of the first structure group and the secondstructure group has a plurality of gear sections on its surface which isin contact with a surface of the other one of the first structure groupand the second structure group; and the plurality of gear sectionsengage with both gear sections of adjacent ones of a plurality ofstructures of the other one of the first structure group and the secondstructure group.
 14. The direct acting extensible and retractable armmechanism as set forth in claim 1, wherein: the robot arm supportingmember is capable of storing, inside the robot arm supporting member,the first structure group and the second structure group which have beenseparated from each other by the separation means; and the firststructure group and the second structure group, separated from eachother by the separation means, are stored along an inner shape of therobot arm supporting member by (i) the rotation of each of the pluralityof first structures via the corresponding one of the plurality of firstcoupling axes and (ii) the rotation of each of the plurality of secondstructures via the corresponding one of the plurality of second couplingaxes.
 15. A robot arm comprising: a direct acting extensible andretractable arm mechanism recited in claim
 1. 16. The robot arm as setforth in claim 15, wherein: one of ends of the arm section of the directacting extensible and retractable arm mechanism is provided with an endeffector.